1. Field of the Invention
The invention relates generally to methods and apparatus in a printing system to integrate ink flush patterns with imprinted data in an ink-based printing system. More specifically, the invention relates to methods and apparatus for allowing user customization of the style and placement of flush patterns to allow useful integration of the flush patterns with the images on a printed page.
2. Discussion of Related Art
In ink-based printing systems (e.g., inkjet and other ink deposition systems) it is often necessary to clean clogged ink deposition nozzles. As the printing system is producing imprinted images on paper (or other printable media), the frequency and volume of ink usage for each of multiple ink colors may vary. Some ink nozzles for some ink colors may be heavily used over a sequence of printed sheets/images while other nozzles associated with other ink colors may be infrequently used or not used at all. These nozzles with limited use may clog if not maintained by a cleaning procedure.
It is generally known to stop the printing process to permit manual intervention to clear all nozzles of an ink-based printing system. The manual intervention may entail purely manual procedures such as actuating a cleaning request option on the operator panel of the printing system. Or, such manual procedures may entail formatting and printing a page/image that intentionally utilizes all ink nozzles or selected ink nozzles to keep the nozzles clean (by flowing a sufficient volume of ink there through). Such manual intervention gives rise to a need for human intervention to clean the nozzles if not also to format a suitable cleaning page/image and to forward the formatted image to the marking engine of the printing system. This manual intervention can cause a significant delay in the continued processing of the printing system. In high-volume production printing systems, such a delay can be very costly.
To avoid the delays inherent in human intervention, it is generally known to provide some automated procedure to flush nozzles of an ink-based printing system without requiring manual intervention and thus without stopping the operation of the printing system to await human intervention. In some known automated techniques, flush lines (e.g., a pattern of pixels typically formatted as lines of varying colors of ink) are added to an imprinted image printed by the printing in its production printing process. Flush lines are most generally rendered graphical images/pixels intended merely to cause ink to flow through all (or selected ones) of the nozzles of the ink-based printer. This flow of ink helps avoid clogging of the nozzles. The graphical image so produced by flush lines as presently practiced is not intended to represent any information meaningful to a user. In prior techniques, such flush lines are placed on the printable medium (e.g., paper) in an area that may be cut away (e.g., “chipped out”).
However, in a large number of printing applications there may be no area of the printable medium that is discarded (e.g., edge to edge printing on the printable medium). Thus a flush of the various ink nozzles either requires the above identified manual intervention or requires that the flush lines be integrated with the printed pages and thus may appear on one or more printed pages potentially occluding data on the printed page. Since the flush pattern may be integrated on the sheetside images, some printing systems allow a simple, pre-defined flush pattern—a line—to be adjusted for placement on the sheetside and for thickness of the flush line to be rendered. However, the flush line still provides no useful purpose on the imprinted sheetside image other than the useful purpose of flushing ink.
It is evident from the above discussion that an ongoing need exists for improved methods and apparatus for performing automated flush procedures for ink-based printing systems where the flush pattern must be integrated with the printed images.